John Deere Mower Stutters and Runs Rough (FIND & FIX)

Your lawnmower’s engine may splutter or run roughly for a number of reasons; start by eliminating potential obstructions to the engine’s air, fuel, and spark. When you’re done, keep an eye out for anything that could cause unnecessary wear and tear on the motor.

Top 12 causes of John Deere lawn mower breakdowns:

  1. Air filter obstruction
  2. Idiotic choking
  3. using fuel
  4. Fuel line clog
  5. Drained fuel filter
  6. Unclean carburetor
  7. Leaky gas cap
  8. Soiled spark plug
  9. Quickness on the ground
  10. Sluggish motor
  11. The Deck of the Mower is Blocked
  12. Sharpening dull mower blades

Wait for the engine to cool and the mower’s moving parts to halt before attempting any maintenance. Before making repairs, remove the spark plug boot(s) and observe the safety procedures outlined in the John Deere manual.

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Before diagnosing, repairing, or operating, be sure you’ve read and understood all of the safety recommendations in the equipment’s operator’s manual. If you are unsure about how to proceed or if you lack the necessary expertise or experience, you should seek the assistance of a professional.

Why Your John Deere Lawnmower Is Running Rough And Sputtering

John Deere Lawnmower with Clogged Air Filter

Cleaning the air filter on a regular basis is important since it can become clogged with debris like grass clippings and grime if it isn’t maintained properly.

It safeguards the engine by letting only clean air into the workings of the engine. When an engine doesn’t have an air filter, the engine can be damaged by dust and other debris.

Your John Deere will start to overheat and smoke if the engine can’t obtain enough fresh air.

Air filters should be cleaned and replaced often during the mowing season, and ideally every year.

If you operate your John Deere in very dusty conditions or if you use your mower more frequently than the typical homeowner, you may need to clean or replace the filter more frequently.

SOLUTION: If the air filter appears to be slightly soiled, clean it. You should get a new air filter whenever the old one becomes too dusty, torn, or unable to form a tight seal over the air intake. To clean your specific air filter, please refer to the guidelines below.

Cleanse a John Deere lawn mower paper air filter:

  • Take off the air filter and put it somewhere safe.
  • Remove any lingering grime from the housing by wiping it down. Don’t let any grime get into the machine’s air filter.
  • Don’t be afraid to bang your filter on something hard. Ideally, you want to loosen and knock out as much dirt from the filter as possible.
  • Make that the air filter still allows light to pass through by holding it up to a light. Air filters can be reused multiple times if they are in good condition. You should get a new one if you can’t fix it.
  • Insert the filter back into the housing and replace the lid.
  • If your air purifier has a foam pre-filter, clean it with a little soap and water. Then, just let it air dry once you’ve given it a good rinsing. The pre-filter should NOT BE oiled.

John Deere Lawn Mower Stuck Choke or Incorrect Choke Setting

While starting a cold engine, the choke is utilized to reduce the amount of air that enters the combustion chamber. More fuel and less air means the mixture can run richer.

After the engine has started and warmed up, the choke lever needs to be moved to the “off” position to allow the engine to draw the additional air it needs to keep running.

Incorrect placement of the John Deere choke, or getting trapped in the open or closed position, can cause the engine to sputter and bog.

When starting the engine from cold, make sure the choke lever is closed; when starting from warm, make sure the lever is open.

If the airflow is restricted even after adjusting the choke lever, verify that the plate is opening and closing properly.

For a blocked choke, try a carburetor cleaner, and if the cable is worn or broken, get a new one.

Using Outdated Fuel in a John Deere Lawnmower

After around 30 days, gas loses its quality and should be replaced. Nevertheless, ethanol, which is present in most gasoline these days, is harmful to the fuel system and the engine.

Ethanol is a renewable fuel alternative added to gas to reduce its environmental impact. It is produced from high-starch plants.

This fuel has a chemical composition that makes it attracted to atmospheric moisture. Gas and water don’t go together. Corrosive ethanol and water will separate from fuel, leaving behind a varnish that will limit fuel flow and eventually cause component failure.

Because of the fuel limits, the engine won’t be able to function as well as it could.

The answer is obvious: new gas should be put into the tank. New gasoline and a fuel system cleaner and stabilizer, such as Sea Foam Motor Treatment, can assist get rid of the sludge and moisture that have built up in the fuel system.

For best performance, fill up with fuel that has an octane rating of 87 or above and contains no more than 10% ethanol. The finest gas is one without ethanol. Check here for advice on picking the proper fuel type: John Deere lawn mowers run on this fuel.

John Deere Mower Fuel Line Clogged

It is possible for the fuel flow to be restricted due to the accumulation of sticky deposits in the fuel system. Checking the flow of fuel out of a line while stopping and starting the flow using the fuel shut-off valve or hose crimp pliers will help you identify a blocked fuel line.

Check the fuel flow when collecting petrol in a container. Keep in mind that this container needs to be positioned underneath the gas tank. Uphill fueling requires a fuel pump since fuel does not flow naturally.

The answer is to disconnect the clogged fuel line and turn off the fuel valve. Spraying carburetor cleaning into the line may help break up the clog and allow gas to flow again.

The next step is to try to clear the blockage by blowing compressed air into the line. Carburetor cleaning and compressed air should be used repeatedly until the clog is removed.

If you find that you are unable to remove the gasoline restriction or that the fuel line is developing cracks, you should replace the fuel line with one of the same length and diameter.

John Deere Lawnmower with a Clogged Fuel Filter

The mower’s fuel system and engine are protected from debris and other impurities by an inline fuel filter. The fuel filter, like the air filter, is a disposable item that must be regularly replaced to ensure clean fuel.

When the gasoline filter gets clogged with grime, the fuel flow is restricted. It’s possible that the engine will bog down and run roughly if the carburetor doesn’t get the fuel it needs.

The fuel filter should be changed once a year at the very least, and more often if it is clogged or broken.

REMEDY: Swap out the clogged old filter with a brand new in-line model. Make sure the arrow on the replacement filter is pointing in the direction of fuel flow by inspecting the filter before installation.

John Deere Lawn Mower with a Filthy Carburetor

The carburetor is the part of the engine that combines fuel and air for combustion. Inadequate fuel-air mixture is one cause of engine shakiness when the carburetor isn’t doing its job.

First, check the fuel supply before blaming a malfunctioning John Deere carburetor for the problem. If you aren’t, maybe your gasoline line is clogged, or the filter is, or the fuel pump is broken.

To proceed, take out the air filter from its housing. Spray some carburetor cleaner into the mower’s air inlet and start it up.

Carburetor cleaning is probably necessary if the engine performs well at first but subsequently loses power.

Clean the carburetor as described in this John Deere lawn mower carburetor care guidelines.

John Deere Lawnmower with a Leaking Gas Cap

The fuel tank can vent properly with a John Deere gas cap since it is perforated. If the gas cap is faulty and doesn’t allow air to enter the tank, the pressure within will build up as gas is used up without being replaced by fresh air.

This vacuum will prevent fuel from leaking out of the tank at a sufficient rate. If your mower is having trouble operating smoothly, check the vacuum in the tank with a pressure gauge or use the guidelines below.

Methods for recognizing a clogged fuel cap vent:

  • To fix a rough running engine, try releasing some air from the fuel cap.
  • There may be a problem with the gas cap’s venting if you see an immediate improvement in the engine’s performance after replacing it.
  • Verify the issue by letting the mower run while making sure the gas cap is securely fastened.
  • When it slows down, have a listen with the cap off. If the engine smooths out when the gas cap is loosened, then the gas cap was likely the source of the problem.

Get a new gas cap for your John Deere and put it on.

A John Deere lawn mower with a dirty spark plug

If the spark plug is fouled, the engine may splutter and run roughly. Spark can also be affected by the electrode gap on the plug and by spark plug wires that have come loose.

The spark plug has to be taken out and looked at. If you notice that the color is really dark, the electrode is burned, or the device is somehow damaged, you should get a new one. Remove the accumulation with a wire brush if it’s in good condition otherwise and only slightly soiled.

Spark plug gap should be checked per engine manufacturer’s recommendation. As a last step, make sure the spark plug wire is firmly fastened.

Too Much Speed on the Ground with a John Deere Lawnmower

Conditions while mowing will dictate how quickly you should move. Lawns with thick, tall, or damp grass need to be mowed more slowly than those with shorter, thinner grass.

Using a ground speed that is too high for the mowing circumstances is hard on the engine and may cause it to stall. Even with a John Deere, you’ll get a subpar cut as a result.

Adjust your ground speed according to the conditions and continue mowing. When you notice that your car’s engine is losing power, it’s time to slow down.

Mowing long grass requires numerous passes. It will take much longer, but you will get cleaner cuts and won’t have to worry about the engine burning out.

Set your mower’s cutting height to its highest setting for the initial cut, and then gradually lower it for subsequent cuts.

John Deere Mowers Have a Too-Slow Engine Speed

A John Deere mower and mower deck require a sizable engine. To prevent the mower from stuttering, it’s best to run the engine at full throttle when you start the blades.

The ANSWER is to increase the engine speed to its maximum capacity by pulling the throttle lever all the way in. Commonly, a rabbit symbol will appear on mowers when this is the case.

John Deere Lawn Mower with a Clogged Deck

When the deck of a mower is clogged with dead grass and other debris, the engine has to work harder to turn the blades.

The engine will struggle to turn the blades through all of this extra weight, and as a result, the vehicle will move more slowly than usual.

To solve this problem, you can use a deck scraper or wire brush to regularly clean the mower deck. Please don’t attempt to trim wet grass. This type of grass is more likely to form clumps and stay adhered to the patio.

Attempting to prevent debris from adhering to the deck with a deck spray is a viable option. That helps, but it’s not a magic bullet that will prevent all grass from sticking to the deck.

John Deere Lawnmower with Dull Blades

In order to get a clean snip with the mower, make sure the blades are sharp. Mowing with dull blades can shred the grass, causing the tips to darken a few days later as a result of trauma.

The problem of a blocked lawn mower deck is exacerbated by dull mower blades, which can also cause the grass to seem poorly mowed. Grass on the deck makes it harder for the mower’s blades to turn, therefore this will just make the engine bog down more.

THE ANSWER: Take the mower blades off the deck. Follow the steps outlined in Change & Sharpen Your John Deere Mower Blades to properly sharpen and balance the blade.

Do You Still Have Issues with Your John Deere Mower?

Inevitably, as a John Deere mower owner, you will face a wide range of issues. Common issues include starting properly, shutting off unexpectedly, vibrating excessively, cutting unevenly, and not moving at all.

I’ve compiled a helpful manual to assist you in diagnosing the issues with your John Deere lawnmower. Check out this article for answers to frequently asked questions about fixing common issues with John Deere lawn mowers.